Vane pump and pressure control means



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A. VON WANGENHEIM VANE PUMP AND PRESSURE CONTROL MEANS- .Fan. 25, 949.

2 Sheets-Sheet 1 Filed Nov. 19, 1942 INVENTQR Von. w

M ATTORNEY Jan. 25, 1949. A. VON WANGENHEIM VANE PUMP AND PRESSURE CONTROL MEANS 2 Sheets-Sheet 2 Filed NOV. 19, 1942 M? Van d BY W1. W0

Ala ATTORNEY Patented Jan. 25,

VANE PUMP AND PRESSURE CONTROL MEANS Adolf von Wangcnheim, Detroit, Mich, assignor to Detroit Lubricator Company, Detroit, Mich, a corporation of Michigan Application November 19, 1942, Serial No. 466,116

6 Claims. 1

This invention relates to new and useful improvements in units for supplying liquid under pressure and more particularlyto a combined pump, pressure regulating means and strainer.

An object of the invention is to provide a unit in which the component parts may be readily assembled with accuracy in commercial quantity production.

Another object is to provide a pump which will be highly efficient in operation and in which pump noises will be substantially eliminated.

Another object is to provide a pressure regulating valve in which hissing or other noise of discharging liquid will be silenced and substantially eliminated.

Another object is to provide efllcient means for sealing a. drive shaft of a pump.

The invention consists in the improved construction of parts and their cooperative relation to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings to be taken as a part of this specification, there is fully and clearly shown a preferred embodiment of the invention, in which drawings:

Figure 1 is a view in front elevation of a com- "bined pump, strainer and pressure regulating valve embodying the invention. but showing the regulating valve in longitudinal central section;

Fig. 2 is a view in section on the line 2-2 of Fig. 1;

Fig. 3 is a detail view in section on the line M of Fig. 1;

Fig. 4 is a detail sectional view' on the line l of Fig. 2;

Fig. 5 is a view in front elevation and partly in section of the pump portion of the unit and with the cover member of this portion removed to show internal construction;

Fig. 6 is a view of the pump substantially in section on the line 6-6 of Fig. 2 so that the front closuremember is removed;

Fig. '7 is a view in section on the line l--| of Fig. 2, thereby showing the other end closure member of the pump in elevation;

Fig. 8 is a view in section on the line 6-4 of Fig. 6;

Fig. 9 is a detail view in section on the line 9-! of Fig. 6, and

' inner peripheral portion of the annular sealing Fig. 10 is a detail view in section on the line l0l6 of Fig. 7.

Referring to the drawings by characters of reference, I designates generally a body or housing member having a chamber 2 formed by a cup-like cover member 3 having a surrounding flange 6 which seats in and against the base of an annular recess in a flat chamber wall 5. Extending from the wall 5 and away from the chamber 2, there is a hollow extension 6 having a bore 1 extending longitudinally therethrough and opening into the chamber 2 through substantiall the middle point of the wall 5. The bore 1 has. intermediate its ends, an enlarged diameter portion 8 and a bearing or guide portion 9 of reduced diameter relative to the diameter of the bore 1. Within the chamber 2 there is a pump casing Ill having end closure plate members ll, l2 between which there is clamped a hollow annular stator member ii. The end closure member l2 has an external fiat face l4 which seats against the flat wall 5. Projecting y from the face It there is a hollow extension l5 which extends through the bore I and fits .the

guide portion 9. The extension l5, except for its fit in the portion 9. is in circumferentially spaced relation to the wall of the bore 1 so as to provide for liquid flow in the bore 1 around the extension IS. The passageways it are provided in the wall of the hollow extension 6 to permit communication between opposite sides of the portion 9. Journaled in the pump casing extension l5 and projecting therefrom, there is a pump drive shaft I! which extends out of the housing extension 6. Surrounding the shaft I1 and screwthreaded, as at l8, into the outer end of the bore 1, there is a closure member H! which tightly clamps the marginal edge portion of a sealing member 20 against an outward facing shoulder 2| in the extension 6. The member 20 is preferably of flexibly resilient sheet materiaLsuch, for example. as a rubber, synthetic rubber. or other organic elastomer having inserted fabric. on the shaft I! there is a two-part thrust member 22 which has a rotary fit on the shaft i1 and between the parts of which there is tightly clamped the member 20. The thrust member 22 is urgedtoward the extension [5 by a coil spring 23 which abuts against the closure member is and urges the thrust member 22 into rotary sealing engageon the shaft 11. The'collarfi is-limited against endwise movement toward the-thrust member-22 by B" split ring or- -wa'sher member 26'which seats in a: circumferential groove 2.1. in: the shaft 11. A'tlii'u'stwasheror-bearing pad "surrounds the shaft. Hand is positioned between the collar 25 and the end face of extension IE to take the thrust of spring 23.

The drive shaft 11 extends through the casing I in eccentric relation to the internally cylindrical surface of the stator member II and is journaled in the end closure member H. Keyed on the shaft l1 and fitting between the closure members Ii, I2, there is a rotor 29 of annular form and concentric with shaft H. The rotor 29 has tangential engagement with the cylindrical surface of stator l3 as at 30, see Fig. 6. Accurate tangential sliding fit is provided by means of the locating pins 3|, 32 which have their longitudinal center lines intersecting an extended line at right angles to and joining the shaft longitudinal center line and the line of tangential contact. The pin 3| fits with the usual commercial clearance in a one diameter hole through the closure members ll, I2 and stator i3 but has its end portions, which are located within the closure members H and 12, cut or formed to provide a diametrieal flat portion which, being transverse to the above mentioned extended line, will permit slight radial movement of the stator toward and from the rotor. Any such radial movement is, however, prevented after tight tangential contact is obtained and this is accomplished by means of the pin 32 which has a tight fit in alined apertures in the closure members II and i2 and also has a tight fit in the bore of a bushing 33, which bore is alined with the closure member apertures. The bushing bore is drilled or formed after the rotor and stator are in tight tangential contact so that no radial play of the stator relative to the rotor is permitted when the pin 32 has been inserted in its locking position. In order to eliminate any possibility of a shifting of the parts H, 12 and 13 relative to each other, they are frictionally clamped tightly to each other by means of screws 34. In the circumference of the rotor 29 there are radial longitudinal slots 35 extending across the face of the rotor and extending radially inward substantially to the inner circumference or marginal edge of annular grooves 36 in the end faces of the rotor and concentric with the shaft l1. There are preferably 6 such slots 35 and they are equally spaced circumferentially of the rotor 29. .In each of the slots 35 and having a radial sliding movement therein, there is a vane member 31. The radial length or depth of the vane members 31 is such that irrespective of the circumferential position of the vane member relative to the stator l3, there will always be a slight extension'of the'vane member into the annular grooves 36. The vane members are, of course, all similar in dimension with respect to each other. Within each of the. grooves 36,

'there is a ring member 33 which has its external circumference fitting against theinner; ends-of the vane. members 31 so as to tend to. hold the vane members 31in contact withthe internally cylindrical surface of the stator 13. Opening from chamber 2. into the end' closure-member ll substantially parallel to the plane, of the rotor 29, there is an inlet conduit 38" which meat with the face of an annular-flange 24 pro- I jecting from a collar" 25, preferably -press4ltted' terminates adjacent the pointer tangential coni tact '30 and in registry with a cross passage 4|!v in the stator l3 and the abutting portion of member l-l. This cross passage-40 opens into the pump inlet port which-Lisain' the form ,of arcuate recesses 41,42 in the innerfa'ces of the end members ll, l2 respectively, and which are in registry with the crescent-shaped space 43 between the rotor and the stator. The inlet ports' 4|, 42 are of arcuate form extending as recesses in the rotor engaging faces of the members II and I2, the recesses being concentric with the shaft l1 and being of a width to extend more than across the space 43. These inlet port recesses are each of a length greater than 120 and each starts, as at 44, closely adjacent but on the inlet side of the point 30. On the opposite side of the point 30 is located the exhaust port which comprises the arcuate recesses 45, 46 respectively in the closure members ll, l2 respectively. The main body portions of the exhaust port recesses 45, 46 are of equal size and extend circumferentially and concentrically of the shaft I1 in registering relation with the crescent-shaped space 43. These main recess portions are of greater width than the space 43 so that they are in opposed relation to the stator and to the rotor. The recess 46 has a leading portion 41 which is of materially reduced V-shaped cross section and extends toward the inlet port to a point so that the distance between the start of the portion 41 and the out 01f end of the port recess 42 is equal to the space between adjacent ones of the vane members 31 at the external circumference of the space 43. It will therefore be apparent that as the space between adjacent vane members is cut off from the recess 42, that it will be substantially simultaneously opened into the leading o exhaust portion 41. This exhaust recess 46 has a materially reduced V-shaped trailing portion 49 which terminates at the point 30 so that there will be no trapping of liquid in the space 43 as the vanes leave the main portion of recess 46. The recess 45 also has a leading portion 50 which is of materially reduced cross section and Vshaped. This leading portion 50 extends toward the inlet port for about two-thirds of the length of the leading portion 41. Through the stator I3 there is an aperture or cross passage 5| which connects the exhaust recesses 45, 46 adjacent the terminal end of the main recess portions. From the main portion of recess 46, there is an exhaust outlet port 52 which opens through the closure member face l4 into registry with an outlet passageway 53 in the. housing member I and opening through the fiat chamber wall 5. Establishing communication from the exhaust port, preferably the main portion of recess 46, there is a conduit 54 which registers with and opens into one of the annular grooves 36, see Fig. 9 so as to subject the inner shaft facing ends of the vane members 31 to the exhaust pressure, thereby to urge the vane members into engagement with the internally cylindrical surface of the stator l3. The exhaust .outlet port 52 is preferably of reduced cross section, as at 55, in order to increase the back pressure in the recess 36 so as to enhance the holding of the vane members in contact with the stator. It will be noted that the recesses or annular grooves 36 are in communication'with each other. through the radial rotor slots 35.

;-Solely by way of example, and without limitation of the relation of the porting in a 6 vane pump, the following spacing may be embodied. Starting from the point 01 contact 38 and traveling counterclockwise, the angular degree distances may be To the start of inlet port-about 15 To the end of inlet port-about 130 To the start of the leading groove 41-about 198 To the start of the leading groove 58--about 228 To the start of main exhaust recesses 45, 48-

about 285 To exhaust port outlet 52about 29s" To the end of main recesses 45, l|i-about 337 56 being of smaller diameter than the holes the casing ||l to the wall 5 by means of screws 56, the screws 51 through the casing l0 through whichjqthe screws 58 pass, so that the extension 5-;,can be accurately alined with the guideportion 8, thereby eliminating any flexing or setting up of twisting stresses in the casing l0.

Within the chamber 2, there is a strainer member 58 of cylindrical form which fits over the closure member i2, which is of somewhat larger diameter than the external diameter of the stator l3 and closure member so as to provide spacing between the pump casing and the internal diameter of the strainer member 58. The housing cover member 3 engages one end face of the strainer member 58 and holds it tightly clamped against the flat chamber wall 5, the strainer member 58 being of an external diameter to provide a clearance space around its external circumference within the cover member 3. This strainer member may be composed of an inner cylinder of foraminous material '58, such as wire screening, which serves as a base or support for a cylindrical pad of filter material 68. The cover pipe or conduit leading member 3 is tightly clamped and sealed in position against the wall 5 by means of clamping screws 8| which engage the cover member flange A.

In the housing member I there is an inlet passageway 82 which opens through the wall 5, as at 83, externally of the strainer member 58 so that fluid flowing through the conduit 82 must pass through the strainer member 58 in order to reach the pump inlet passageway 38. The inlet conduit 62 may have a pipe or other conduit member 84 secured thereto and leading from a source of fluid supply. The outlet conduit 53 from the pump extends through the wall of the housing and opens, as at 85, into a pressure regulating valve means 68 and particularly into the pressure chamber 61 thereof. The regulating means 66 also includes a by-pass chamber 88 and these chambers 81 and 68 are separated by a pressure responsive member 89, preferably a sheet of flexible, stretchable, resilient material, such, for example, as Ameripol. Between the chambers 61, 88, the housing member has an internal annular shoulder 10 on which the marginal portion of the member 89 seats. A clamping ring and guide member 1| overlies the shoulder 1'8 and clamps the marginal edge of the member 89 in tight sealing relation thereto. The ring member 1| is held in position by a hollow clamplug nut 12 screw-threaded within the chamber 58. Slidably guided within the'ring member 1|,

, there is a cup-shaped backing member 13 havspring 11 which 6 ing its base portion seating on the pressure responsive diaphragm member 69. Through the diaphragm member 69 and the cup member base portion, there is a central alined opening through which there extends a tubular valve seat and guide member 14 having an annular clamping flange which seats against and tightly clamps the diaphragm member 89 to the cup member base portion. The seat member 14 extends through the cup member base portion and is rigidly secured thereto and has a projecting end portion within the chamber 88. Within the cup member 13 and seating on its base, there is a silencer disc'member 15 of flexible, stretchable, resilient material, such, for example, as a rubber, synthetic rubber, or other organic elastomer and having a small opening 15 therethrough registering with the bore of the seat member 14. This silencer member 15 is held at its marginal edge portion tightly against the bottom of the cup member 13 by a flanged washer 18 having a tight flt in the cup member 13 and by a helical coil seats at one end on the washer 16. The spring 11, at its other end, abuts an adjustment abutment means 18 by which the force of the spring 11 can be adjusted to determine the force acting on diaphragm member 69 in chamber 61, which will move the diaphragm member 88 toward the by-pass chamber 68. Leading from the by-pass chamber 88 through the wall of housing member there is a'by-pass conduit 18*, which opens at its outlet end, as at 19, into the bore 1 around the extension i5 and between chamber 8 and the valve casing closure of bore 1. The fluid which empties into chamber 8 through conduit outlet 19 is free to pass through a port 88, see Fig. 3, into a passageway 8| which opens at its lower'end, as at 82, externally of the housing I for connection of a back, for example, to the source of fluid supply. The other or upper end of this passageway 8| may be closed by a screw plug 83, thereby closing off communication between the passageway 8| and a passageway 84 which opens into the chamber 2, as at 85, see Fig. 5. If desired, the passage outlet 82 may be closed by a plug and the plug 83 removed, so that flow from passageway 8| will pass through passageway 84 into the chamber 2 and return to the pump inlet passageway 39, The pressure chamber 81 has an outlet port or passageway 86 controlled by valve means 81, which is preferably in the form of a double ended valve member also controlling the flow through the seat member 14, into the by-pass chamber 68. The bore of the seat member 14 provides a by-pass outlet from the pressure chamber 61. The valve member end portion cooperable with the seat member a bleed slot 88, so that any entrapped air or gas will be discharged and not cause the pump to lose its prime or be air bound. The spring 11 urges the seat member 14 into closing relation against the double ended valve member 81 and urges this member 81 into closing relation with the outlet 88. A' spring 89 tends to move the valve means 81 into open relation preferably has with respect to the outlet 88 and does so move the valve member 81 when pressure in the chamber 61 moves the diaphragm member 88 upward or toward the by-pass chamber 88. A stop member 90 is provided to limit the movement of valve means 81 by the spring 89, so that when the valve means has been opened a predetermined distance, the seat member 14 can thereupon move away from the valve means 81 to open the bypass port into the by-pass chamber 68.

This action of the valve means 81 is well understood in the art and no further explanation is therefore necessary.

The operation of this combined pump, regulating means and strainer unit and of the parts of the same is as follows. It is, of course, assumed that the unit is utilized for supplying oil to an oil burner, for example, so that the outlet 8G is connected to the burner and the inlet conduit 64 is connected to a source of liquid fuel, and the outlet 82 is connected'back to the fuel source. When the pump is started by counterclockwise rotation of shaft I'I facing Figs. 1, 5, 6 and 7 and as indicated by the arrow a, Fig. 6, a vacuum will be created in the first half of the crescent-shaped space 43 by the vane members 31, thereby drawing oil into the chamber 2 through the inlet conduit 62. This oil in chamber 2 will be drawn through the strainer member 58 and through the inlet passageway 39 to the pump inlet port 4!, 42. The oil supplied to inlet port 4|, 42 will fill the expanding space between the rotor 29 and the stator l3 and the adjacent vane members. When a vane member, such as the member 31, see Fig. 6, leaves its inlet port, it will cut off communication of the inlet port with the space which precedes it, and as this vane member 31 passes the middle point of the crescent-shaped space 43, the vane member will start to compress the liquid between it and its preceding vane member. Substantially simultaneously with the cut off of the inlet port by the vane member 31 the space preceding this vane member will be opened into the leading exhaust groove 41, so that the bleeding of the liquid through this groove and the main exhaust recess portion '46 will cause a gradual discharge of the compressed liquid, thereby eliminating pump noise. As the vane member continues past the inlet of groove 41, it will come to the inlet or start of the exhaust bleed groove 50, thereby increasing the bleeding of oil into the main portionof the exhaust outlet 48 during the increasing compression on the oil. As the vane reaches the main exhaust recess portions 45, 48,the oil ahead of the vane member and between the stator and rotor will be forced out into the exhaust port and any oil which is retained ahead of the vane member after the vane member leaves the main recess portions 45, 46 will be discharged back into the main recess portions 45, 46 through the trailing groove 49. The oil discharged into the discharge recesses 45, 48 which are in communication through the cross passage will be forced through the discharge outlet 52 and the restricted port 55 into the outlet passageway 53. Due to the conduit, oil will, of course, be held under compression in the annular grooves 36, thereby maintaining the vane members in contact with the cylindrical stator surface.

The oil which is discharged through the passageway 53 will be fed into the pressure chamber 61, see Fig. 1, and when the pressure has built up so that the force exerted against the diaphragm 89 is sufficient to overcome the force of the compression regulating spring 11, then the diaphragm member 69 will be moved toward the by-pass chamber 68, thus permitting the valve means 81 to move toward open position or upward, thereby permitting the discharge of oil through the outlet passage '86 to the burner. When the pump gets up to speed and is discharging oil at a rate to create the maximum desired pressure in chamber 61 and at the burner,

then the stop 90 will limit further opening of the outlet 86 and upon any pressure increase,.the diaphragm member 69 will move away from the valve means 87, thereby opening the by-pass port through seat member 14. The extent of opening at the valve seat member I4 will, of course, vary with the pressure in chamber 61. The oil discharging. into chamber 68 will be fed therefrom through the passageway 18 into the chamber 8 and thence throughport 80 to the outlet of passage 8! which leads back to the supply tank. If, as abovenoted, the outlet 82 is closed by a plug and the screw plug 83 is removed, then this by-pass oil will be discharged thorugh the by-pass 84 back into the chamber 2 for return to the pump.

The silencing feature of the pressure regulating means functions by automatically controlling the fiow area of the small opening The pressure in chamber 61, which is sufliclent to lift the diaphragm member 69, will, if its flow is at a greater rate than can be handled by the small opening 15, cause the disc member 15 to stretch upward, thereby increasing the size of the small opening 15. Therefore, instead of the oil which discharges through the seat member 14 being sprayed into the chamber 68 with a hissing noise, the oil will be confined by the port or small opening 15 and be discharged into chamber 68 as a solid stream. It will, of course, be apparent that the size of the opening 15 will vary automatically, in accordance with the pressure of the liquids against the inlet side of the disc member I It will, of course, be apparent that the pump and regulating means are each capable of separate use, but that they arehere disclosed in mutually cooperative relation by reason of the particular ports and passageways.

What is claimed and is desired to be secured by Letters Patent of the United States is:

1. A pump comprising a casing having internal opposed side walls joined, by an internally cylindrical imperforate surface, a drive shaft journaled in said casing eccentric to said surface, a cylindrical rotor on and concentric with said shaft and having tangential contact with said surface, radially movable equi-spaced vane members carried by said rotor and contacting said surface, said casing having in at least one of its side walls an inlet port extending circumferentially of said rotor and opening transversely to the plane of the rotor into the space between said rotor and said'surface and beginning adjacent the line of" said tangential contact, said casing having in at least one of its side walls an exhaust port extending circumferentially of said rotor and opening transversely to the plane of the rotor into the space between said rotor and said surface and ending substantially at the line vof said tangential contact such that said inlet port and said exhaust port are spaced at said line or contact a distance less than the space between adjacent vane members, and said inlet port terminating and said exhaust port beginning at points spaced substantially equi-distant to the spacing between said vane members at said surface, said exhaust port having a leading portion of reduced cross-sectional area relative to the remainder of said exhaust port and extending circumferentially of said rotor in a direction opposite to the rotation of said rotor.

2. A pump comprising a hollow casing having end plate members and a hollow member therebetween having an internally cylindrical imperforate surface, a drive shaft-journaled in said casing and extending into said hollow member eccentric to said surface, a rotor concentric with and fixed on said shaft within said hollow memher and having tangential contact with said surface, radially movable equi-spaced vane members carried by said rotor and contacting said surface, at least one of said plate members havin in its side face an inlet port beginning adjacent the line of said tangential contact and extending circumferentially of said rotor, said inlet port opening transversely to the plane of said rotor into the space between said rotor and said surface, at least one of said plate members having in its side face an exhaust port terminating at the line of said tangential contact and extending circumferentially ofsaid rotor, said exhaust port opening transversely to the plane of said rotor into said space between said rotor and said surface, the inlet port terminating and said exhaust port beginning a distance from each other substantially equal to the distance at said surface between adjacent ones of said vane members, said exhaust port having a leading groove of reduced cross-sectional area relative to said exhaust port opening'thereinto and extending circumferentially of said rotor in a direction opposite to the rotation of said rotor and of a length at least as long as the distance between adjacent ones of said vane members, said exhaust port having a trailing groove of reduced cross-sectional area relative to said exhaust port opening therefrom and extending circumferentially of said rotor in the direction of rotation of said rotor and terminating substantially at the line of said tangential contact, and said casing having an inlet passageway leading to said inlet port and an outlet pasageway leading from said exhaust port.

3. A pump comprising a hollow casing having end plate members and a hollow member therebetween having an internally cylindrical imperforate surface, a drive shaft journaled in said casing and extending into said hollow member eccentric to said surface, a rotor concentric with and fixed on said shaft within said hollow member and having tangential contact with said surface, radially movable' equi-spaced vane members carried by said rotor and contacting said surface,

said plate members each having an arcuate inlet recess positioned axially of and at the ends of said rotor, said recesses being in opposed coextensive relation to each other and providing an inlet port beginning adjacent and on the inlet side of the line of said tangential contact, said hollow member having a passageway directly connecting said recesses, said recesses extending circumferentially of said rotor and opening transversely to the plane of said rotor into the space between said rotor and said surface, said plate members each having an arcuate exhaust recess positioned axially of and at the ends of said rotor, said exhaust recesses being-in opposed coextensive relation to each other and. each having a leading groove of reduced cross-sectional area relative to and opennig into its exhaust recess, and extending circumferentially of said rotor in a direction opposite to the rotation of said rotor, one of said leading grooves beginning a distance from said inlet port substantially equal to the distance at said surface between adjacent ones of said vane members, the other of said leading grooves beginning a distance from said inlet port substantially one and one half times the distance at said surface between said vane members, said plate member having said one leading groove also having a trailing groove of reduced crosssectional area relative to and opening into its exhaust recess, and extending circumferentially of said rotor in the direction of rotation of said rotor, said trailing groove terminating substantially at the line of said tangential contact, said exhaust recesses, said leading grooves and said trailing groove cooperating to provide an exhaust port extending circumferentially of said rotor and opening transversely to the plane of said rotor into the space between said rotor and said surface, sald hollow member having a passageway directly connecting said exhaust recesses, said plate member having said other leading groove also having an inlet passageway opening into its said inlet recess adjacent the lineof said tangential contact, and said plate member having said one leading groove also having an outlet passageway opening from its said exhaust recess adjacent said leading grooves, and means to supply fluid at exhaust pressure to the shaft facing sides of said vane members.

4. A pump comprising a casing having end plate members and a hollow member therebetween having an internally cylindrical surface, a drive shaft journaled in said plate members and extending through said hollow member eccentric to said surface, a rotor on and concentric with said shaft within said hollow member and having tangential contact with said surface, radially movable equi-spaced vane members carried by said. rotor and contacting said surface, said plate members and said hollow member having a one-diameter hole therethrough with its'longitudinal centerline intersecting an extended line at right angles to and joining the shaft centerline and the line of said tangential contact, a pin member-in said hole and permitting slight radial movement of said hollow member to assure absolute contact between said surface and said rotor, said plate members having alined one-diameter holes having their common centerline intersecting said extended line on the opposite side of said shaft from said first-named hole, said hollow member having a hole therethrough alined with and of larger diameter than said alined holes, a bushing member in said last-named hole, and a pin member tightly fitting said alined holes and said bushing member thereby to hold said hollow member and said rotor in said tangential contact with each other.

5. In a vane type pump, a casing having end plate members and a hollow member therebetween having an internally cylindrical surface, a drive shaft journaled in said plate members and extending through said hollow member eccentric to said surface, a rotor fixed on and concentric with said shaft within said hollow member and having tangential contact with said surface, said plate members and said hollow member having a one-diameter hole therethrough with its longitudinal centerline intersecting an extended line at right angles to and joining the shaft centerline and the line of said tangential contact, a pin member in said hole and permitting slight radial movement of said hollow member to assure absolute contact between said surface and said rotor, said plate members having alined one-diameter holes having their common centerline intersecting said extended line on the opposite side of said shaft from said first-named hole, said hollow member having a hOle therethrough alined with and of larger diameter than said alined holes, a bushing member in said last-named hole and having a hole therethrough of equal diameter to said alined holes and positioned concentrio with said alined holes when said rotor and surface are in said tangential contact, and a pin member tightly fitted in and through said bushing hole and said allned holes thereby to hold said hollow member and said rotor in said tangential contact with each other.

6. A pump comprising a hollow casing having an internally cylindrical imperforate surface and a flat side face, a drive shaft eccentric to said surface, a cylindrical rotor on and concentric with said shaft and having solely a substantially single line tangential contact with said surface, radially movable equi-spaced vane members carried by said rotor and contacting said surface, a flat end plate member closing said casing and abutting, said rotor, said plate member having circumferentially spaced arcuate slots therein registering transversely to the plane of said rotor with the space between said rotor and said surface, one of said slots being aninlet port and starting substantially at said tangential contact, the other of said slots being an exhaust port having a main portion and an arcuate leading portion extending in a direction opposite to the direction of rotation of said rotor and an arcuate trailing portion extending in the direction of rotation of said rotor, said leading portion being of equal and uniform cross-section substantially throughout its length and being of a length greater than the distance between adjacent vane members, said trailing portion terminating subequal and uniform cross-section substantially throughout its length, and said main portion being of greater cross-section than said leading and trailing portions and of a' length greater Itohan the distance between adjacent vane memers.

ADOLF VON WANGENHEIM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,505,982 Traudt Aug. 26, 1924 1,722,616 Williams July 30, 1929 1,953,606 Hobson Apr. 3, 1934 2,013,777 Dennedy Sept. 10, 1935 2,133,708 Larson Oct. 18, 1938 2,141,170 Centervall Dec. 27, 1938 2,165,963 Curtis July 11, 1939 2,174,869 Czarnecki Oct. 3, 1939 2,193,075 Osborne Mar. 12, 1940 2,257,702 Murphy Sept. 30, 1941 2,309,803 Wahlmark Feb. 2, 1943 2,335,284 Kendrick Nov, 30, 1943 FOREIGN PATENTS Number Country Date 220,600 Great Britain Feb. 26, 1925 243,388 Great Britain Nov. 23, 1925 

